Hi I haven't had a period in 3 months nearly and haven't had sex or done anything that might enable me to be pregant in over a year. I have been told that this may be due to stress as the last time i had a period I was in a very stressful job which i quit and went into my last month of final year uni assignments etc. I am starting to worry and I was thinking about going to see my GP. has anyone got any ideas behind the reason?

You should definitely see your GP. A period stopping is called "amenorrhea" ... if you Google this, plenty of sites will come up that provide possible reasons why your period may have stopped. You have secondary amenorrhea (primary means you never got your period in the first place), and there are lots of reasons why it happens. Some are things like stress, others are more serious like cysts or cancer.